Vehicle, vehicle control system, and vehicle control method

ABSTRACT

A vehicle includes: a battery pack including a secondary battery, a battery sensor configured to detect a state of the secondary battery, and a first control device; and a second control device provided separately from the battery pack, wherein: the first control device is configured to set a power upper limit value indicating an upper limit value of a battery power of the secondary battery by using a detection value of the battery sensor; and the second control device is configured to set a guard value of the upper limit value of the battery power by using a temperature of the secondary battery and set the power upper limit value such that the power upper limit value does not exceed the guard value.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No.2019-229537 filed on Dec. 19, 2019, incorporated herein by reference inits entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a vehicle, a vehicle control system,and a vehicle control method.

2. Description of Related Art

Japanese Unexamined Patent Application Publication No. 2019-156007 (JP2019-156007 A) discloses a control device that controls input power of asecondary battery mounted on a vehicle by using a power upper limitvalue (Win) indicating an upper limit value of the input power of thesecondary battery.

SUMMARY

Electrically driven vehicles (for example, electric vehicles or hybridvehicles) that use a secondary battery as a power source have spread inrecent years. In the electrically driven vehicles, when the capacity orthe performance of the secondary battery decreases due to batterydeterioration or the like, it is conceivable that the secondary batterymounted on the electrically driven vehicle is replaced.

The secondary battery is generally mounted on a vehicle in the form of abattery pack. The battery pack includes a secondary battery, a sensorthat detects the state of the secondary battery (for example, current,voltage, and temperature), and a control device. Hereinafter, thecontrol device incorporated in the battery pack may be referred to as“battery electronic control unit (ECU)”, and the sensor incorporated inthe battery pack may be referred to as “battery sensor”. Peripheraldevices (for example, a sensor and a control device) suitable for thesecondary battery are mounted on the battery pack. The battery pack ismaintained so that the secondary battery and its peripheral devices canoperate normally. Therefore, when replacing the secondary batterymounted on the vehicle, it is considered preferable to replace not onlythe secondary battery but the entire battery pack mounted on the vehiclefrom the viewpoint of vehicle maintenance.

As described in JP 2019-156007 A, there is known the control device thatis mounted on the vehicle separately from the battery pack and thatcontrols the input power of the secondary battery by using the powerupper limit value. The control device is configured to performpower-based input restriction. The power-based input restriction is aprocess of controlling the input power of the secondary battery so thatthe input power of the secondary battery does not exceed the power upperlimit value. In general, a vehicle that employs a control device thatperforms the power-based input restriction is equipped with a batterypack including a battery ECU that obtains a power upper limit valueusing a detection value from a battery sensor.

However, when the entire battery pack is replaced, and, for example,when the battery pack after replacement is an inexpensive battery pack,the output result of the battery ECU after the replacement is notnecessarily the same as that of the battery ECU before the replacementdue to the difference in calculation accuracy of the battery ECUs beforeand after the replacement. Therefore, it is required to monitor thesuitability of the output result from the battery pack considering thepossibility of the replacement of the battery pack and restraininput/output power of the secondary battery from becoming excessive.

The present disclosure provides a vehicle, a vehicle control system, anda vehicle control method that enables monitoring of the suitability ofan output result from a battery pack and suppresses the input/outputpower of a secondary battery from becoming excessive.

A vehicle according to an aspect of the present disclosure includes: abattery pack including a secondary battery, a battery sensor configuredto detect a state of the secondary battery, and a first control device;and a second control device provided separately from the battery pack.The first control device is configured to set a power upper limit valueindicating an upper limit value of a battery power of the secondarybattery by using a detection value of the battery sensor. The secondcontrol device is configured to set a guard value of the upper limitvalue of the battery power by using a temperature of the secondarybattery and set the power upper limit value such that the power upperlimit value does not exceed the guard value.

A vehicle control system according to a second aspect of the presentdisclosure is configured such that a battery pack including a secondarybattery is mountable on the vehicle control system. The vehicle controlsystem includes: a control unit configured to control battery power ofthe secondary battery such that the battery power does not exceed apower upper limit value indicating an upper limit value of the batterypower of the secondary battery when the battery pack is mounted on thevehicle control system; and a setting unit configured to, when the powerupper limit value is input from the battery pack, set a guard value ofthe upper limit value of the battery power by using a temperature of thesecondary battery, and set the power upper limit value such that thepower upper limit value does not exceed the guard value.

A vehicle control method according to a third aspect of the presentdisclosure includes: obtaining, with a vehicle control system on which abattery pack including a secondary battery is mounted, a power upperlimit value indicating an upper limit value of a battery power of thesecondary battery from the battery pack; setting, with the vehiclecontrol system, a guard value of the upper limit value of the batterypower by using a temperature of the secondary battery; and setting, withthe vehicle control system, the power upper limit value such that thepower upper limit value does not exceed the guard value.

According to the present disclosure, a vehicle, a vehicle controlsystem, and a vehicle control method that enable monitoring of thesuitability of an output result from a battery pack and suppressinput/output power of a secondary battery from becoming excessive can beprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance ofexemplary embodiments of the disclosure will be described below withreference to the accompanying drawings, in which like signs denote likeelements, and wherein:

FIG. 1 is a diagram showing a configuration of an electrically drivenvehicle according to an embodiment of the present disclosure;

FIG. 2 is a diagram showing a connection mode of each control deviceincluded in the vehicle according to the embodiment of the presentdisclosure;

FIG. 3 is a diagram showing an example of a map used for determiningtarget battery power;

FIG. 4 is a diagram showing a detailed configuration of a battery pack,a hybrid vehicle (HV) electronic control unit (ECU), and a gateway ECU;

FIG. 5 shows an example of a map showing a predetermined relationshipbetween the temperature of a battery 11 and a guard value;

FIG. 6 is a diagram showing a detailed configuration of a battery pack10 and an HV ECU 50 in a modified example; and

FIG. 7 is a diagram showing a detailed configuration of a battery pack,an HV ECU, and a gateway ECU in another modified example.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will be described in detail withreference to the drawings. It should be noted that the same orcorresponding parts in the drawings are denoted by the same referencecharacters and repetitive description thereof will be omitted.Hereinafter, an electronic control unit is also referred to as “ECU”.

FIG. 1 is a diagram showing a configuration of an electrically drivenvehicle (hereinafter referred to as “vehicle”) 100 according to anembodiment of the present disclosure. In the present embodiment, thevehicle 100 is assumed to be a front-wheel drive four-wheel vehicle(more specifically, a hybrid vehicle), but the number of wheels and thedrive system can be changed as appropriate. For example, the drivesystem may be rear-wheel drive or four-wheel drive.

Referring to FIG. 1 , the vehicle 100 is equipped with a battery pack 10including a battery ECU 13. Further, a motor ECU 23, an engine ECU 33,an HV ECU 50, and a gateway ECU 60 are mounted on the vehicle 100separately from the battery pack 10. The motor ECU 23, the engine ECU33, the HV ECU 50, and the gateway ECU 60 are located outside thebattery pack 10. The battery ECU 13 is located inside the battery pack10. In the present embodiment, the battery ECU 13, the gateway ECU 60,and the HV ECU 50 correspond to examples of a “first control device”, a“second control device”, and a “third control device” according to thepresent disclosure, respectively.

The battery pack 10 includes a battery 11, a voltage sensor 12 a, acurrent sensor 12 b, a temperature sensor 12 c, the battery ECU 13, anda system main relay (SMR) 14. The battery 11 functions as a secondarybattery. In the present embodiment, an assembled battery including aplurality of electrically connected lithium ion batteries is adopted asthe battery 11. Each secondary battery that constitutes the assembledbattery is also referred to as a “cell”. In the present embodiment, eachlithium-ion battery that constitutes the battery 11 corresponds to the“cell”. The secondary battery included in the battery pack 10 is notlimited to the lithium ion battery and may be another secondary battery(for example, a nickel metal hydride battery). An electrolytic solutionsecondary battery or an all-solid-state secondary battery may be used asthe secondary battery.

The voltage sensor 12 a detects the voltage of each cell of the battery11. The current sensor 12 b detects current flowing through the battery11 (the charging side takes a negative value). The temperature sensor 12c detects the temperature of each cell of the battery 11. The sensorsoutput the detection results to the battery ECU 13. The current sensor12 b is provided in the current path of the battery 11. In the presentembodiment, one voltage sensor 12 a and one temperature sensor 12 c areprovided for each cell. However, the present disclosure is not limitedto this, and one voltage sensor 12 a and one temperature sensor 12 c maybe provided for each set of multiple cells, or only one voltage sensor12 a and one temperature sensor 12 c may be provided for one assembledbattery. Hereinafter, the voltage sensor 12 a, the current sensor 12 b,and the temperature sensor 12 c are collectively referred to as “batterysensor 12”. The battery sensor 12 may be a battery management system(BMS) that has a state of charge (SOC) estimation function, a state ofhealth (SOH) estimation function, a cell voltage equalization function,a diagnostic function, and a communication function in addition to theabove sensor functions.

The SMR 14 is configured to switch connection and disconnection of powerpaths connecting external connection terminals T1 and T2 of the batterypack 10 and the battery 11. For example, an electromagnetic mechanicalrelay can be used as the SMR 14. In the present embodiment, a powercontrol unit (PCU) 24 is connected to the external connection terminalsT1 and T2 of the battery pack 10. The battery 11 is connected to the PCU24 via the SMR 14. When the SMR 14 is in the closed state (connectedstate), power can be transmitted between the battery 11 and the PCU 24.In contrast, when the SMR 14 is in the open state (disconnected state),the power paths connecting the battery 11 and the PCU 24 aredisconnected. In the present embodiment, the SMR 14 is controlled by thebattery ECU 13. The battery ECU 13 controls the SMR 14 according to aninstruction from the HV ECU 50. The SMR 14 is in the closed state(connected state) when vehicle 100 is traveling, for example.

The vehicle 100 includes an engine 31, a first motor generator 21 a(hereinafter referred to as “MG 21 a”), and a second motor generator 21b (hereinafter referred to as “MG 21 b”) as power sources for traveling.The MG 21 a and the MG 21 b are motor generators that have both afunction as a motor that outputs torque by receiving drive power and afunction as a generator that generates electric power by receiving thetorque. An alternating current (AC) motor (for example, a permanentmagnet synchronous motor or an induction motor) is used as the MG 21 aand the MG 21 b. The MG 21 a and the MG 21 b are electrically connectedto the battery 11 via the PCU 24. The MG 21 a has a rotor shaft 42 a andthe MG 21 b has a rotor shaft 42 b. The rotor shaft 42 a corresponds toa rotation shaft of the MG 21 a, and the rotor shaft 42 b corresponds toa rotation shaft of the MG 21 b.

The vehicle 100 further includes a single-pinion planetary gear 42. Anoutput shaft 41 of the engine 31 and the rotor shaft 42 a of the MG 21 aare connected to the planetary gear 42. The engine 31 is, for example, aspark-ignition internal combustion engine including a plurality ofcylinders (for example, four cylinders). The engine 31 combusts fuel ineach cylinder to generate drive force, and the generated drive forcerotates a crankshaft (not shown) shared by all the cylinders. Thecrankshaft of the engine 31 is connected to the output shaft 41 via atorsional damper (not shown). The output shaft 41 rotates along withrotation of the crankshaft.

The planetary gear 42 has three rotating elements, namely, an inputelement, an output element, and a reaction force element. Morespecifically, the planetary gear 42 includes a sun gear, a ring gearthat is arranged coaxially with the sun gear, a pinion gear that mesheswith the sun gear and the ring gear, and a carrier that holds the piniongear so that the pinion gear can rotate and revolve. The carriercorresponds to the input element, the ring gear corresponds to theoutput element, and the sun gear corresponds to the reaction forceelement.

The engine 31 and the MG 21 a are mechanically connected to drive wheels45 a and 45 b via the planetary gear 42. The output shaft 41 of theengine 31 is connected to the carrier of the planetary gear 42. Therotor shaft 42 a of the MG 21 a is connected to the sun gear of theplanetary gear 42. The torque output from the engine 31 is input to thecarrier. The planetary gear 42 is configured to divide the torque outputfrom the engine 31 to the output shaft 41 into torque that istransmitted to the sun gear (eventually the MG 21 a) and torque that istransmitted to the ring gear. When the torque output from engine 31 isoutput to the ring gear, reaction torque generated by the MG 21 a actson the sun gear.

The planetary gear 42 and the MG 21 b are configured such that the driveforce output from the planetary gear 42 and the drive force output fromthe MG 21 b are combined and transmitted to the drive wheels 45 a and 45b. More specifically, an output gear (not shown) that meshes with adriven gear 43 is attached to the ring gear of the planetary gear 42. Adrive gear (not shown) attached to the rotor shaft 42 b of the MG 21 balso meshes with the driven gear 43. The driven gear 43 combines thetorque output from the MG 21 b to the rotor shaft 42 b and the torqueoutput from the ring gear of the planetary gear 42. The drive torquethus combined is transmitted to a differential gear 44 and furthertransmitted to the drive wheels 45 a and 45 b via drive shafts 44 a and44 b extending from the differential gear 44 to the right and left.

The MG 21 a is provided with a motor sensor 22 a that detects the state(for example, current, voltage, temperature, and rotation speed) of theMG 21 a. The MG 21 b is provided with a motor sensor 22 b that detectsthe state (for example, current, voltage, temperature, and rotationspeed) of the MG 21 b. The motor sensors 22 a and 22 b output theirdetection results to the motor ECU 23. The engine 31 is provided with anengine sensor 32 that detects the state of the engine 31 (for example,intake air amount, intake pressure, intake temperature, exhaustpressure, exhaust temperature, catalyst temperature, engine coolanttemperature, and engine speed). The engine sensor 32 outputs itsdetection result to the engine ECU 33.

The HV ECU 50 is configured to output a command (control command) forcontrolling the engine 31 to the engine ECU 33. The engine ECU 33 isconfigured to control various actuators of the engine 31 (for example, athrottle valve, an ignition device, and an injector (not shown)) inaccordance with the command from the HV ECU 50. The HV ECU 50 canperform engine control through the engine ECU 33.

The HV ECU 50 is configured to output a command (control command) forcontrolling each of the MG 21 a and the MG 21 b to the motor ECU 23. Themotor ECU 23 is configured to generate current signals (for example,signals indicating the magnitude and the frequency of the current) thatmatch the target torque of each of the MG 21 a and the MG 21 b inaccordance with the command from the HV ECU 50, and output the generatedcurrent signals to the PCU 24. The HV ECU 50 can perform motor controlthrough the motor ECU 23.

The PCU 24 includes, for example, two inverters each corresponding tothe MG 21 a and the MG 21 b, and a converter arranged between eachinverter and the battery 11. The PCU 24 is configured to supply poweraccumulated in the battery 11 to each of the MG 21 a and the MG 21 b,and supply electric power generated by each of the MG 21 a and the MG 21b to the battery 11. The PCU 24 is configured such that the states ofthe MG 21 a and the MG 21 b can be controlled separately, and, forexample, the MG 21 b can be in the power running state while the MG 21 ais in the regenerative state (that is, the power generation state). ThePCU 24 is configured to be able to supply the electric power generatedby one of the MG 21 a and the MG 21 b to the other. The MG 21 a and theMG 21 b are configured to be able to transmit and receive power to andfrom each other.

The vehicle 100 is configured to perform hybrid vehicle (HV) travelingand electric vehicle (EV) traveling. The HV traveling is travelingperformed by operating the engine 31 and the MG 21 b with the engine 31generating driving force for travel. The EV traveling is travelingperformed by operating the MG 21 b with the engine 31 stopped. When theengine 31 is stopped, combustion is not performed in the cylinders. Whenthe combustion in the cylinders is stopped, the engine 31 does notgenerate combustion energy (the driving force for travel). The HV ECU 50is configured to switch between the EV traveling and the HV travelingdepending on the situation.

FIG. 2 is a diagram showing a connection mode of each control deviceincluded in the vehicle 100 according to the embodiment of the presentdisclosure. Referring to FIG. 2 , the vehicle 100 includes a local busB1 and a global bus B2. The local bus B1 and the global bus B2 are, forexample, controller area network (CAN) buses.

The battery ECU 13, the motor ECU 23, and the engine ECU 33 areconnected to the local bus B1. Although not shown, for example, a humanmachine interface (HMI) control device is connected to the global busB2. Examples of the HMI control device include a control device thatcontrols a navigation system or a meter panel. The global bus B2 isconnected to another global bus via a central gateway (CGW) not shown.

The HV ECU 50 is connected to the global bus B2. The HV ECU 50 isconfigured to perform CAN communication with each control deviceconnected to the global bus B2. The HV ECU 50 is connected to the localbus B1 via the gateway ECU 60. The gateway ECU 60 is configured to relaycommunication between the HV ECU 50 and each control device (forexample, the battery ECU 13, the motor ECU 23, and the engine ECU 33)that is connected to the local bus B1. The HV ECU 50 is configured tomutually perform CAN communication with each control device connected tothe local bus B1 via the gateway ECU 60. As described above, in thepresent embodiment, a vehicle control system is constituted by thecontrol devices connected to the local bus B1.

In the present embodiment, a microcomputer is used as the battery ECU13, the motor ECU 23, the engine ECU 33, the HV ECU 50, and the gatewayECU 60. The battery ECU 13 includes a processor 13 a, a random accessmemory (RAM) 13 b, a storage device 13 c, and a communication interface(I/F) 13 d. The motor ECU 23 includes a processor 23 a, a RAM 23 b, astorage device 23 c, and a communication I/F 23 d. The engine ECU 33includes a processor 33 a, a RAM 33 b, a storage device 33 c, and acommunication I/F 33 d. The HV ECU 50 includes a processor 50 a, a RAM50 b, a storage device 50 c, and a communication I/F 50 d. The gatewayECU 60 includes a processor 60 a, a RAM 60 b, a storage device 60 c, anda communication I/F 60 d. A central processing unit (CPU), for example,can be used as the processors. Each communication I/F includes a CANcontroller. Each RAM functions as a working memory that temporarilystores data processed by the processor. Each storage device isconfigured to be able to save stored information. Each storage deviceincludes, for example, a read-only memory (ROM) and a rewritablenonvolatile memory. Each storage device stores, in addition to aprogram, information that is used in the program (for example, a map, amathematical expression, and various parameters). Various controls ofthe vehicle are executed when the processors execute the programs storedin the storage devices. However, the present disclosure is not limitedto this, and various controls may be executed by dedicated hardware(electronic circuit). The number of processors included in each ECU isnot limited, and any ECU may include a plurality of processors.

Charge/discharge control of the battery 11 will be described referringto FIG. 1 again. Hereinafter, the input power of the battery 11 and theoutput power of the battery 11 are collectively referred to as “batterypower”. The HV ECU 50 determines target battery power using the SOC ofthe battery 11. Then, the HV ECU 50 controls charge/discharge of thebattery 11 so that the battery power becomes closer to the targetbattery power. However, such charge/discharge control of the battery 11is restricted by input/output restriction described later. Hereinafter,the target battery power on the charging side (input side) may bereferred to as “target input power”, and the target battery power on thedischarging side (output side) may be referred to as “target outputpower”. In the present embodiment, the power on the discharging side isrepresented by a positive (+) value and the power on the charging sideis represented by a negative (−) value. However, when comparing themagnitude of the power, the absolute value is used regardless of thepositive or negative sign (+/−). That is, the magnitude of the power issmaller as the value becomes closer to zero. When an upper limit valueand a lower limit value are set for the power, the upper limit value islocated on the side where the absolute value of the power is large, andthe lower limit value is located on the side where the absolute value ofthe power is small. The power exceeding the upper limit value on thepositive side means that the power becomes larger on the positive sidethan the upper limit value (that is, the power moves away to thepositive side with respect to zero). The power exceeding the upper limitvalue on the negative side means that the power becomes larger on thenegative side than the upper limit value (that is, the power moves awayto the negative side with respect to zero). The SOC indicates theremaining charge amount and, for example, the ratio of the currentcharge amount to the charge amount in the fully charged state isrepresented by a range between 0% and 100%. As the measuring method ofthe SOC, a known method such as a current integration method or an opencircuit voltage (OCV) estimation method can be adopted.

FIG. 3 is a diagram showing an example of a map used for determining thetarget battery power. In FIG. 3 , a reference value C₀ indicates acontrol center value of the SOC, a power value P_(A) indicates the upperlimit value of the target input power, and a power value P_(B) indicatesthe upper limit value of the target output power. Referring to FIG. 3together with FIG. 1 , according to this map, when the SOC of thebattery 11 is the reference value C₀, the target battery power is “0”,and the battery 11 is neither charged nor discharged. In the regionwhere the SOC of the battery 11 is smaller than the reference value C₀(excessive discharge region), the target input power is larger as theSOC of the battery 11 is smaller until the target input power reachesthe upper limit value (power value P_(A)). In contrast, in a regionwhere the SOC of the battery 11 is larger than the reference value C₀(overcharge region), the target output power is larger as the SOC of thebattery 11 is larger until the target output power reaches the upperlimit value (power value P_(B)). The HV ECU 50 determines the targetbattery power in accordance with the map shown in FIG. 3 , and chargesand discharges the battery 11 so that the battery power becomes closerto the determined target battery power, thereby bringing the SOC of thebattery 11 closer to the reference value C₀. The reference value C₀ ofthe SOC may be a fixed value or may be variable depending on thesituation of the vehicle 100.

The HV ECU 50 is configured to perform input restriction and outputrestriction of the battery 11 using the battery ECU 13 and the gatewayECU 60.

The battery ECU 13 is configured to use the detection value of thebattery sensor 12 to obtain an upper limit value PWin of the input powerof the battery 11 as a provisional value. The battery ECU 13 is alsoconfigured to use the detection value of the battery sensor 12 to obtainan upper limit value PWout of the output power of the battery 11 as aprovisional value.

The gateway ECU 60 is interposed between the battery pack 10 and the HVECU 50, and uses the upper limit value PWin and the upper limit valuePWout that are output from the battery pack 10 to set a final upperlimit value Win of the input power and a final upper limit value Wout ofthe output power. Thereby, the final upper limit value Win and the finalupper limit value Wout are input to the HV ECU 50.

The HV ECU 50 uses the final upper limit value Win and the final upperlimit value Wout that are input from the gateway ECU 60 to control thebattery power. That is, the HV ECU 50 controls the engine 31 and the PCU24 to adjust the battery power so that the battery power does not exceedthe final upper limit value Win and the final upper limit value Wout.Therefore, for example, when the final upper limit value Win or thefinal upper limit value Wout is smaller (that is, closer to zero) thanthe target battery power, the battery power is controlled to the finalupper limit value Win or the final upper limit value Wout instead of thetarget battery power. In this way, the HV ECU 50 can appropriatelyperform power-based input restriction and power-based output restrictionon the battery 11 included in the battery pack 10.

In the vehicle 100 having the above-described configuration, it isconceivable to replace the battery 11 mounted on the vehicle 100 whenthe capacity or performance of the battery 11 decreases due to batterydeterioration or the like.

The battery 11 is generally mounted on vehicle 100 in the form of thebattery pack 10 as described above. Peripheral devices (for example, thebattery sensor 12 and the battery ECU 13) suitable for the battery 11are mounted on the battery pack 10 as described above. The battery pack10 is maintained so that the battery 11 and its peripheral devices canoperate normally. Therefore, when replacing the battery 11 mounted onthe vehicle 100, it is considered preferable to replace not only thebattery 11 but the entire battery pack 10 mounted on the vehicle 100from the viewpoint of vehicle maintenance.

However, when the entire battery pack is replaced, and, for example,when the battery pack after replacement is an inexpensive battery pack,the output result of the battery ECU after the replacement is notnecessarily the same as that of the battery ECU before the replacementdue to the difference in calculation accuracy of the battery ECUs beforeand after the replacement. Therefore, it is required to monitor thesuitability of the output result from the battery pack 10 (specifically,the battery ECU 13) considering the possibility of the replacement ofthe battery pack 10 and restrain the input/output power of the battery11 from becoming excessive.

Therefore, in the present embodiment, the battery ECU 13 and the gatewayECU 60 operate as follows. That is, the battery ECU 13 uses thedetection value of the battery sensor 12 to set the power upper limitvalues PWin and PWout, which indicate the upper limit values of thebattery power of the battery 11. The gateway ECU 60 uses the temperatureof the battery 11 to set guard values GWin and GWout of the upper limitvalues of the battery power and to set the power upper limit values Winand Wout so that the power upper limit values Win and Wout do not exceedthe guard values.

In this way, when the battery ECU 13 sets the power upper limit valuesPWin and PWout to excessively large values for some reason, theinput/output power of the battery 11 can be protected by the guardvalues GWin and GWout that are set by the gateway ECU 60.

Hereinafter, detailed configurations of the battery ECU 13, the HV ECU50, and the gateway ECU 60 in the present embodiment will be described.

FIG. 4 is a diagram showing a detailed configuration of the battery pack10, the HV ECU 50, and the gateway ECU 60. Referring to FIG. 4 togetherwith FIG. 2 , in the present embodiment, the battery 11 included in thebattery pack 10 is an assembled battery including a plurality of cells111. Each cell 111 is, for example, a lithium ion battery. Each cell 111includes a positive electrode terminal 111 a, a negative electrodeterminal 111 b, and a battery case 111 c. In the battery 11, thepositive electrode terminal 111 a of one cell 111 and the negativeelectrode terminal 111 b of another cell 111 adjacent to the one cell111 are electrically connected to each other by a bus bar 112 havingconductivity. The cells 111 are connected to each other in series.

The battery pack 10 includes the battery sensor 12, the battery ECU 13,and the SMR 14 in addition to the battery 11. Signals output from thebattery sensor 12 to the battery ECU 13 (hereinafter also referred to as“battery sensor signals”) include a signal indicating voltage VB outputfrom the voltage sensor 12 a and a signal indicating current IB outputfrom the current sensor 12 b, and a signal indicating temperature TBoutput from the temperature sensor 12 c. The voltage VB indicates ameasured value of the voltage of each cell 111. The current IB indicatesa measured value of the current flowing through the battery 11 (thecharging side takes a negative value). The temperature TB indicates ameasured value of the temperature of each cell 111.

The battery ECU 13 repeatedly obtains the latest battery sensor signals.The interval at which the battery ECU 13 obtains the battery sensorsignals (hereinafter also referred to as “sampling cycle”) may be afixed value or may be variable. In the present embodiment, the samplingcycle is 8 ms. However, the present disclosure is not limited to this,and the sampling cycle may be variable within a predetermined range (forexample, a range between 1 msec to 1 sec).

The battery ECU 13 includes a PWin calculation unit 131 and a PWoutcalculation unit 132. The PWin calculation unit 131 is configured to usethe detection value of the battery sensor 12 (that is, the batterysensor signals) to obtain the upper limit value PWin. A known method canbe used as the calculation method of the upper limit value PWin. ThePWin calculation unit 131 may determine the upper limit value PWin sothat the charge power restriction is performed to protect the battery11. The upper limit value PWin may be determined to suppress overcharge,Li deposition, high rate deterioration, and battery overheating in thebattery 11, for example. The PWout calculation unit 132 is configured touse the detection value of the battery sensor 12 (that is, the batterysensor signals) to obtain the upper limit value PWout. A known methodcan be used as the calculation method of the upper limit value PWout.The PWout calculation unit 132 may determine the upper limit value PWoutso that the discharge power restriction is performed to protect thebattery 11. The upper limit value PWout may be determined to suppressoverdischarge, Li deposition, high rate deterioration, and batteryoverheating in the battery 11, for example. In the battery ECU 13, forexample, the PWin calculation unit 131 and the PWout calculation unit132 are implemented by the processor 13 a shown in FIG. 2 and theprogram executed by the processor 13 a. However, the present disclosureis not limited to this, and the PWin calculation unit 131 and the PWoutcalculation unit 132 may be implemented by dedicated hardware(electronic circuit).

The battery pack 10 outputs the upper limit value PWin calculated by thePWin calculation unit 131, the upper limit value PWout calculated by thePWout calculation unit 132, and the signals input from the batterysensor 12 (that is, the battery sensor signals) as a command signal S1to the gateway ECU 60. These pieces of information are output from thebattery ECU 13 included in the battery pack 10 to the gateway ECU 60provided outside the battery pack 10. As shown in FIG. 2 , the batteryECU 13 and the gateway ECU 60 exchange information through CANcommunication.

The gateway ECU 60 includes a GWin calculation unit 61, a Win settingunit 62, a GWout calculation unit 63, and a Wout setting unit 64, whichwill be described below. In the gateway ECU 60, for example, the GWincalculation unit 61, the Win setting unit 62, the GWout calculation unit63, and the Wout setting unit 64 are implemented by the processor 60 ashown in FIG. 2 and the program executed by the processor 60 a. However,the present disclosure is not limited to this, and the PWin calculationunit 131 and the PWout calculation unit 132 may be implemented bydedicated hardware (electronic circuit).

The GWin calculation unit 61 is configured to use the detection value ofthe battery sensor 12 separately from the battery ECU 13 to obtain theguard value GWin of the upper limit value of the input power. In thepresent embodiment, the GWin calculation unit 61 determines the guardvalue GWin using the temperature TB, for example. The GWin calculationunit 61 determines the guard value GWin using, for example, thetemperature TB and a map or a mathematical expression, etc. showing apredetermined relationship between the temperature TB and the guardvalue GWin.

FIG. 5 shows an example of a map showing a predetermined relationshipbetween the temperature TB of the battery 11 and the guard values GWinand GWout. The vertical axis in FIG. 5 indicates the guard values GWinand GWout. The horizontal axis in FIG. 5 indicates the temperature TB ofthe battery 11. A line L11 in FIG. 5 indicates the relationship betweenthe temperature TB and the guard value GWin. A line L12 in FIG. 5indicates the relationship between the temperature TB and the guardvalue GWout. The map shown in FIG. 5 is stored in advance in the storagedevice 60 c (FIG. 2 ).

As indicated by the line L11 in FIG. 5 , the temperature TB and theguard value GWin have the following relationship. The guard value GWinis constant at a predetermined value when the temperature TB changesfrom TB (1) to TB (2). When the temperature TB is lower than TB (1), themagnitude of the guard value GWin becomes smaller as the temperature TBdecreases. When the temperature TB is higher than TB (2), the magnitudeof the guard value GWin becomes smaller as the temperature TB increases.The GWin calculation unit 61 calculates the guard value GWin inaccordance with the temperature TB based on the line L11 in FIG. 5 .Instead of the measured value of the temperature TB, for example, anyone of average cell temperature, maximum cell temperature, and minimumcell temperature may be used as the temperature TB.

Returning to FIG. 4 , the Win setting unit 62 is configured to use theguard value GWin input from the GWin calculation unit 61 and theprovisional value PWin input from the battery ECU 13 to obtain the upperlimit value Win of the input power. When the magnitude of theprovisional value PWin is equal to or smaller than the magnitude of theguard value GWin, the Win setting unit 62 sets the provisional valuePWin as the upper limit value Win of the input power. In contrast, whenthe magnitude of the provisional value PWin is larger than the magnitudeof the guard value GWin, the Win setting unit 62 sets the guard valueGWin as the upper limit value Win of the input power.

The GWout calculation unit 63 is configured to use the detection valueof the battery sensor 12 separately from the battery ECU 13 to obtainthe guard value GWout of the upper limit value of the output power. Inthe present embodiment, the GWout calculation unit 63 determines theguard value GWout using the temperature TB, for example. The GWoutcalculation unit 63 determines the guard value GWout using, for example,the temperature TB and a map or a mathematical expression, etc. showinga predetermined relationship between the temperature TB and the guardvalue GWout.

As indicated by the line L12 in FIG. 5 , the temperature TB and theguard value GWout have the following relationship. The guard value GWoutis constant at a predetermined value when the temperature TB changesfrom TB (1) to TB (2). When the temperature TB is lower than TB (1), themagnitude of the guard value GWout becomes smaller as the temperature TBdecreases. When the temperature TB is higher than TB (2), the magnitudeof the guard value GWout becomes smaller as the temperature TBincreases. The GWout calculation unit 63 calculates the guard valueGWout in accordance with the temperature TB based on the line L12 inFIG. 5 .

Returning to FIG. 4 , the Wout setting unit 64 is configured to use theguard value GWout input from the GWout calculation unit 63 and theprovisional value PWout input from the battery ECU 13 to obtain theupper limit value Wout of the output power. When the magnitude of theprovisional value PWout is equal to or smaller than the magnitude of theguard value GWout, the Wout setting unit 64 sets the provisional valuePWout as the upper limit value Wout of the output power. In contrast,when the magnitude of the provisional value PWout is larger than themagnitude of the guard value GWout, the Wout setting unit 64 sets theguard value GWout as the upper limit value Wout of the output power.

Thus, when the provisional values PWin and PWout and the battery sensorsignals are input from the battery pack 10 to the gateway ECU 60, theupper limit value Win of the input power is set by the GWin calculationunit 61 and the Win setting unit 62, and the upper limit value Wout ofthe output power is set by the GWout calculation unit 63 and the Woutsetting unit 64. Then, the upper limit values Win and Wout and thebattery sensor signals are output from the gateway ECU 60 to the HV ECU50 as a command signal S2. As shown in FIG. 2 , the gateway ECU 60 andthe HV ECU 50 exchange information through CAN communication.

The HV ECU 50 includes a control unit 51 described below. In the HV ECU50, for example, the control unit 51 is implemented by the processor 50a shown in FIG. 2 and the program executed by the processor 50 a.However, the present disclosure is not limited to this, and the controlunit 51 may be implemented by dedicated hardware (electronic circuit).

The control unit 51 is configured to use the upper limit value Win tocontrol the input power of the battery 11. Further, the control unit 51is configured to use the upper limit value Wout to control the outputpower of the battery 11. In the present embodiment, the control unit 51creates a control command S_(M1) for the MG 21 a shown in FIG. 1 , acontrol command S_(M2) for the MG 21 b shown in FIG. 1 , and a controlcommand SE for the engine 31 shown in FIG. 1 such that the input powerof the battery 11 does not exceed the upper limit value Win and theoutput power of the battery 11 does not exceed the upper limit valueWout. The control unit 51 outputs a command signal S3 including thecontrol command S_(M1) for the MG 21 a, the control command S_(M2) forthe MG 21 b, and the control command SE for the engine 31 to the gatewayECU 60. The control commands S_(M1) and S_(M2) of the command signal S3output from the HV ECU 50 are sent to the motor ECU 23 via the gatewayECU 60. The motor ECU 23 controls the PCU 24 (FIG. 1 ) in accordancewith the received control commands S_(M1) and S_(M2). The controlcommand SE of the command signal S3 output from the HV ECU 50 is sent tothe engine ECU 33 via the gateway ECU 60. The engine ECU 33 controls theengine 31 in accordance with the received control command SE. Bycontrolling the MG 21 a, the MG 21 b, and the engine 31 in accordancewith the control commands S_(M1), S_(M2), and SE, respectively, theinput power of the battery 11 is controlled so as not to exceed theupper limit value Win, and the output power of the battery 11 iscontrolled so as not to exceed the upper limit value Wout. The HV ECU 50can adjust the input power and the output power of the battery 11 bycontrolling the engine 31 and the PCU 24.

As described above, the vehicle 100 according to the present embodimentincludes the battery pack 10 including the battery ECU 13, and the HVECU 50 and the gateway ECU 60 that are provided separately from thebattery pack 10. The gateway ECU 60 is configured to relay communicationbetween the battery ECU 13 and the HV ECU 50. The gateway ECU 60 isequipped with the GWin calculation unit 61, the Win setting unit 62, theGWout calculation unit 63, and the Wout setting unit 64. The Win settingunit 62 sets the upper limit value Win of the input power based on thecomparison result of the guard value GWin obtained by the GWincalculation unit 61 and the provisional value PWin input from thebattery pack 10. Therefore, for example, when the magnitude of theprovisional value PWin is equal to or smaller than the magnitude of theguard value GWin, the Win setting unit 62 sets the provisional valuePWin as the upper limit value Win, and when the magnitude of theprovisional value PWin exceeds the magnitude of the guard value GWin(when the magnitude of the provisional value PWin is lower than the lineL11 in FIG. 5 ), the Win setting unit 62 sets the guard value GWin asthe upper limit value Win.

The Wout setting unit 64 sets the upper limit value Wout of the outputpower based on the comparison result of the guard value GWout obtainedby the GWout calculation unit 63 and the provisional value PWout inputfrom the battery pack 10. Therefore, for example, when the magnitude ofthe provisional value PWout is equal to or smaller than the magnitude ofthe guard value GWout, the Wout setting unit 64 sets the provisionalvalue PWout as the upper limit value Wout, and when the magnitude of theprovisional value PWout exceeds the magnitude of the guard value GWout(when the magnitude of the provisional value PWout is higher than theline L12 in FIG. 5 ), the Wout setting unit 64 sets the guard valueGWout as the upper limit value Wout.

The HV ECU 50 is configured to use the upper limit value Win input fromthe gateway ECU 60 to control the input power of the battery 11.Further, the HV ECU 50 is configured to use the upper limit value Woutinput from the gateway ECU 60 to control the output power of the battery11. Therefore, the HV ECU 50 can appropriately perform the power-basedinput restriction and the power-based output restriction using the upperlimit values Win and Wout, respectively.

In this way, in the battery ECU 13, when the magnitudes of theprovisional values PWin and PWout of the power upper limit values becomeexcessively large for some reason, the battery 11 can be protected bythe guard values GWin and GWout. In other words, it is possible tomonitor the suitability of the provisional values PWin and PWout of thepower upper limit values calculated in the battery ECU 13 and restrainthe input/output power of the battery 11 from becoming excessive. Thus,the present disclosure can provide a vehicle and a vehicle controlsystem that monitor the suitability of the output result from thebattery pack 10 and suppress the input/output power of the secondarybattery from becoming excessive.

Further, by setting the guard values GWin and GWout in the gateway ECU60, the input/output power of the battery 11 can be protected, and thecommunication between the battery ECU 13 and the HV ECU 50 is relayed bythe gateway ECU 60 so that the battery ECU 13 and the HV ECU 50 canfunction in cooperation with each other to control the battery power ofthe secondary battery without changing the configurations of the batteryECU 13 and the HV ECU 50.

Further, the gateway ECU 60 sets the guard values GWin and GWout usingthe detection values of the battery sensor 12 that are used when thebattery ECU 13 sets the provisional values PWin and PWout of the powerupper limit values, and thus the suitability of the output result of thebattery ECU 13 can be determined with high accuracy.

Further, the vehicle control system on which the battery pack 10 ismounted and that includes the HV ECU 50 and the gateway ECU 60 asdescribed above can control the input/output power of the battery 11with the vehicle control method including the first to third stepsdescribed below.

In the first step, the vehicle control system obtains the provisionalvalues PWin and PWout of the upper limit values of the battery power ofthe battery 11 from the battery pack 10. In the second step, the vehiclecontrol system uses the temperature TB of the battery 11 to set theguard values GWin and GWout of the upper limit values of the batterypower. In the third step, the vehicle control system sets the powerupper limit values Win and Wout so that the power upper limit value Windoes not exceed the guard value GWin and the power upper limit valueWout does not exceed the guard value GWout.

With the first to third steps, a vehicle control method that enablesmonitoring of the suitability of the output result from the battery pack10 and suppresses input/output power of the secondary battery frombecoming excessive can be provided.

Hereinafter, modified examples will be described. In the above-describedembodiment, the gateway ECU 60 uses the temperature TB of the battery 11to set the guard values GWin and GWout of the upper limit values of thebattery power. Alternatively, the SOC of the battery 11 may be used inaddition to the temperature TB of the battery 11 to set the guard valuesGWin and GWout of the upper limit values of the battery power when theupper limit values of the battery power of the battery 11 are dependenton the SOC of the battery 11 in addition to the temperature TB of thebattery 11.

Furthermore, in the above-described embodiment, the case where thebattery ECU 13, the motor ECU 23, and the engine ECU 33 are connected tothe local bus B1 has been described as an example, but the motor ECU 23and the engine ECU 33 may be connected to the global bus B2.

Furthermore, in the above-described embodiment, the configuration of thehybrid vehicle as shown in FIG. 1 has been described as an example ofthe configuration of the electrically driven vehicle, but theconfiguration is not particularly limited to the hybrid vehicle. Theelectrically driven vehicle may be, for example, an electric vehiclethat is not equipped with an engine, or a plug-in hybrid vehicle (PHV)configured to be able to charge a secondary battery in a battery packusing electric power supplied from outside the vehicle.

Furthermore, in the above-described embodiment, the configuration inwhich the HV ECU 50 controls the SMR 14 via the battery ECU 13 has beendescribed as an example, but the HV ECU 50 may be configured to directlycontrol the SMR 14 without using the battery ECU 13.

Furthermore, in the above-described embodiment, the case where thebattery 11 (secondary battery) included in battery pack 10 is anassembled battery has been described as an example, but the battery 11may be, for example, a single battery.

Furthermore, in the above-described embodiment, the configuration of thevehicle control system in which the HV ECU 50 and the gateway ECU 60 areprovided as separate ECUs has been described as an example.Alternatively, for example, the vehicle control system may include anECU in which the HV ECU 50 and the gateway ECU 60 are integrated intoone ECU.

FIG. 6 is a diagram showing a detailed configuration of the battery pack10 and the HV ECU 50 in a modified example. In this modified example,the vehicle control system has a configuration in which the function ofthe gateway ECU 60 shown in FIG. 4 is incorporated in the HV ECU 50, andthe HV ECU 50 corresponds to an example of the “second control device”.

The battery pack 10 shown in FIG. 6 has the same configuration as thebattery pack 10 shown in FIG. 4 . Thus, detailed description of theconfiguration of the battery pack 10 will not be repeated.

The configuration of the HV ECU 50 shown in FIG. 6 is different from theconfiguration of the HV ECU 50 shown in FIG. 4 in that the HV ECU 50shown in FIG. 6 includes a GWin calculation unit 52, a Win setting unit53, a GWout calculation unit 54, and a Wout setting unit 55. The GWincalculation unit 52, the Win setting unit 53, the GWout calculation unit54, and the Wout setting unit 55 respectively correspond to the GWincalculation unit 61, the Win setting unit 62, the GWout calculation unit63, and the Wout setting unit 64 included in the gateway ECU 60 shown inFIG. 4 . Thus, detailed description of the configuration of the GWincalculation unit 52, the Win setting unit 53, the GWout calculation unit54, and the Wout setting unit 55 will be omitted.

By setting the guard values GWin and GWout in the HV ECU 50, theinput/output power of the battery 11 can be protected, and the batteryECU 13 and the HV ECU 50 can function in cooperation with each other tocontrol the battery power of the battery 11 without adding the gatewayECU 60.

Further, in the above-described embodiment, the gateway ECU 60 sets theguard values GWin and GWout using the detection values of the batterysensor 12 that are used when the battery ECU 13 sets the provisionalvalues PWin and PWout of the power upper limit values. Alternatively,for example, the guard values GWin and GWout may be set using thedetection value of a temperature sensor that is provided separately fromthe battery sensor 12 and that detects the temperature of the battery11.

FIG. 7 is a diagram showing a detailed configuration of the battery pack10, the HV ECU 50, and the gateway ECU 60 in another modified example.

The configuration of the battery pack 10 shown in FIG. 7 is differentfrom the configuration of the battery pack 10 shown in FIG. 4 in that atemperature sensor 15 is provided in the battery 11 in addition to thetemperature sensor 12 c of the battery sensor 12. Other configurationsof the battery pack 10 shown in FIG. 7 are the same as the configurationof the battery pack 10 shown in FIG. 4 . Thus, detailed description ofthe battery pack 10 will not be repeated.

The temperature sensor 15 is provided in any one of the plurality ofcells constituting the battery 11 and detects a temperature TB′ of thebattery 11. As with the temperature sensor 12 c, the temperature sensor15 may be provided, for example, for each of the cells constituting thebattery 11, or one temperature sensor 15 may be provided for each set ofmultiple cells.

A signal indicating the temperature TB′ detected by the temperaturesensor 15 is output to the gateway ECU 60 as a command signal S4 that isdifferent from the command signal from the battery ECU 13. Thetemperature TB′ input to the gateway ECU 60 is input to each of the GWincalculation unit 61 and the GWout calculation unit 63. The GWincalculation unit 61 and the GWout calculation unit 63 use thetemperature TB′ and the map shown in FIG. 5 to calculate the guardvalues GWin and GWout, respectively.

In this way, the gateway ECU 60 sets the guard values GWin and GWoutusing the detection value of the temperature sensor 15 providedseparately from the battery sensor 12, and thus the suitability of theoutput result of the battery ECU 13 can be determined with high accuracyeven when a failure occurs in the battery sensor 12.

Furthermore, in the above-described embodiment, the temperature TB ofthe battery 11 is used to set the guard values GWin and GWout of theupper limit values of the battery power, but instead of setting theguard values of the upper limit values of the battery power, the guardvalues of allowable current during the charge/discharge may be set. Thegateway ECU 60 sets the guard values of the allowable current during thecharge/discharge, for example, by dividing the guard values GWin andGWout of the upper limit values of the battery power by the voltage VBof the battery 11. When the provisional values of the allowable currentare input from the battery pack 10 and the magnitudes of the provisionalvalues are larger than the magnitudes of the guard values, the gatewayECU 60 outputs the guard values to the HV ECU 50 as the allowablecurrent. In contrast, when the magnitudes of the provisional values aresmaller than the magnitudes of the guard values, the gateway ECU 60outputs the provisional values to the HV ECU 50 as the allowablecurrent. The HV ECU 50 controls the battery power of the battery 11 sothat the battery current does not exceed the allowable current inputfrom the gateway ECU 60.

Further, in the above-described embodiment, the upper limit values Winand Wout are set by the comparison result between the provisional valuesPWin and PWout of the upper limit values of the battery power and theguard values GWin and GWout, and the battery power is controlled so asnot to exceed the set upper limit values Win and Wout. Alternatively,the SMR 14 may be controlled to the disconnected state, or in additionto or instead of controlling the SMR 14 to the disconnected state, abattery-less traveling may be performed in which the MG21 b is drivenusing the electric power generated by the MG21 a with the operation ofthe engine 31 and without using the electric power of the battery 11,when the state in which the magnitude of the provisional value PWin islarger than the magnitude of the guard value GWin continues until apredetermined time elapses or when the state in which the magnitude ofthe provisional value PWout is larger than the magnitude of the guardvalue GWout continues until a predetermined time elapses.

The above-described modified examples may be carried out byappropriately combining all or part thereof. The embodiments disclosedherein should be considered as illustrative and not restrictive in allrespects. The scope of the present disclosure is shown by the claims,rather than the above embodiments, and is intended to include allmodifications within the meaning and the scope equivalent to those ofthe claims.

A vehicle according to an aspect of the present disclosure includes: abattery pack including a secondary battery, a battery sensor configuredto detect a state of the secondary battery, and a first control device;and a second control device provided separately from the battery pack.The first control device is configured to set a power upper limit valueindicating an upper limit value of a battery power of the secondarybattery by using a detection value of the battery sensor. The secondcontrol device is configured to set a guard value of the upper limitvalue of the battery power by using a temperature of the secondarybattery and set the power upper limit value such that the power upperlimit value does not exceed the guard value.

With this configuration, when the first control device sets the powerupper limit value to an excessively large value for some reason, theinput/output power of the secondary battery can be protected by theguard value that is set by the second control device.

In the above aspect of the present disclosure, the vehicle may furtherinclude a third control device provided separately from the battery packand configured to control the battery power such that the battery powerdoes not exceed the power upper limit value set by the second controldevice. The second control device may be configured to relaycommunication between the first control device and the third controldevice.

With this configuration, by setting the guard value in the secondcontrol device, the input/output power of the secondary battery can beprotected, and communication between the first control device and thethird control device is relayed so that the first control device and thethird control device can function in cooperation with each other tocontrol the battery power of the secondary battery without changing theconfigurations of the first control device and the third control device.

In the above aspect of the present disclosure, the second control devicemay be configured to control the battery power such that the batterypower does not exceed the power upper limit value that has been set.

With this configuration, by setting the guard value in the secondcontrol device, the input/output power of the secondary battery can beprotected, and the first control device and the second control devicecan function in cooperation with each other to control the battery powerof the secondary battery.

In the above aspect of the present disclosure, the battery sensor mayinclude a temperature sensor configured to detect the temperature of thesecondary battery. The second control device may be configured to setthe guard value by using a detection value of the temperature sensor.

With this configuration, the second control device sets the guard valueby using the detection value of the battery sensor used when the firstcontrol device sets the power upper limit value, and thus thesuitability of the output result of the first control device can bedetermined with high accuracy.

In the above aspect of the present disclosure, the vehicle may furtherinclude a temperature sensor provided separately from the battery sensorand configured to detect the temperature of the secondary battery. Thesecond control device may be configured to set the guard value by usinga detection value of the temperature sensor.

With this configuration, the second control device sets the guard valueusing the detection value of the temperature sensor provided separatelyfrom the battery sensor, and thus the suitability of the output resultof the first control device can be determined with high accuracy evenwhen a failure occurs in the battery sensor.

In the above aspect of the present disclosure, the power upper limitvalue set by the first control device may be a provisional power upperlimit value which is set provisionally as the power upper limit value.The second control device may be configured to set the power upper limitvalue by comparing the provisional power upper limit value and the guardvalue.

In the above aspect of the present disclosure, the second control devicemay be configured to set the provisional power upper limit value as thepower upper limit value when the provisional power upper limit value isequal to or smaller than the guard value, and set the guard value as thepower upper limit value when the provisional power upper limit value islarger than the guard value.

A vehicle control system according to a second aspect of the presentdisclosure is configured such that a battery pack including a secondarybattery is mountable on the vehicle control system. The vehicle controlsystem includes: a control unit configured to control battery power ofthe secondary battery such that the battery power does not exceed apower upper limit value indicating an upper limit value of the batterypower of the secondary battery when the battery pack is mounted on thevehicle control system; and a setting unit configured to, when the powerupper limit value is input from the battery pack, set a guard value ofthe upper limit value of the battery power by using a temperature of thesecondary battery, and set the power upper limit value such that thepower upper limit value does not exceed the guard value.

A vehicle control method according to a third aspect of the presentdisclosure includes: obtaining, with a vehicle control system on which abattery pack including a secondary battery is mounted, a power upperlimit value indicating an upper limit value of a battery power of thesecondary battery from the battery pack; setting, with the vehiclecontrol system, a guard value of the upper limit value of the batterypower by using a temperature of the secondary battery; and setting, withthe vehicle control system, the power upper limit value such that thepower upper limit value does not exceed the guard value.

What is claimed is:
 1. A vehicle comprising: a battery pack including asecondary battery, a battery sensor configured to detect a state of thesecondary battery, and a first control device; a second control deviceprovided separately from the battery pack, wherein: the first controldevice is configured to set a power upper limit value indicating anupper limit value of a battery power of the secondary battery by using adetection value of the battery sensor; and the second control device isconfigured to set a guard value of the upper limit value of the batterypower by using a temperature of the secondary battery, and set the powerupper limit value such that the power upper limit value does not exceedthe guard value; and a third control device provided separately from thebattery pack and configured to control the battery power such that thebattery power does not exceed the power upper limit value set by thesecond control device, wherein: the second control device is configuredto relay communication between the first control device and the thirdcontrol device, and the second control device is different than andseparate from the third control device.
 2. The vehicle according toclaim 1, wherein the second control device is configured to control thebattery power such that the battery power does not exceed the powerupper limit value that has been set.
 3. The vehicle according to claim1, wherein: the battery sensor includes a temperature sensor configuredto detect the temperature of the secondary battery; and the secondcontrol device is configured to set the guard value by using a detectionvalue of the temperature sensor.
 4. The vehicle according to claim 1,further comprising a temperature sensor provided separately from thebattery sensor and configured to detect the temperature of the secondarybattery, wherein the second control device is configured to set theguard value by using a detection value of the temperature sensor.
 5. Thevehicle according to claim 1, wherein the power upper limit value set bythe first control device is a provisional power upper limit value whichis set provisionally as the power upper limit value, and the secondcontrol device is configured to set the power upper limit value bycomparing the provisional power upper limit value and the guard value.6. The vehicle according to claim 5, wherein the second control deviceis configured to set the provisional power upper limit value as thepower upper limit value when the provisional power upper limit value isequal to or smaller than the guard value, and set the guard value as thepower upper limit value when the provisional power upper limit value islarger than the guard value.